The disclosure relates to a unit and method for warning a driver who drives a vehicle in a fast lane at low speed over a long time.
Many roads, especially high speed roads, have two or more lanes in a driving direction, among which there is a fast lane in which vehicles are allowed to run at high speed. For example, in countries with right-hand traffic, the left most lane of the road lanes in the same direction is the fast lane. Some fast lanes are also called as overtaking lanes in which vehicles are allowed to run when their speeds reach a certain required level. There are generally allowed speed ranges for the lanes of a road, and the allowed speed range for a fast lane is higher than other lanes. When a vehicle runs in a fast lane, it is not allowed to run at a speed higher than the higher speed limit or lower than the lower speed limit of the allowed speed range. If the vehicle runs in a fast lane at a speed that is lower than the lower speed limit of the allowed speed range for a long time without reasons, the vehicle will hinder other vehicles behind it, and those vehicles have to overtake it from right side, which breaks the left side overtake regulation and may result in traffic accidents.
For vehicles running in a fast lane at low speed over a long time, not all the drivers drive the vehicles in this way intentionally. Some drivers just do not realize that they are driving the vehicle too slow. Thus, it is advantageous to warn them in this condition.